I. Measurement Posture and Operating Procedures
1. Sitting posture requirements: The patient should sit with their back against a chair, feet flat on the ground, and arm at heart level. The lower edge of the cuff should be 2-3 cm above the elbow crease, and the tightness should be such that one finger can be inserted underneath.
Incorrect posture (such as arm hanging freely or legs crossed) may lead to "false hypertension," resulting in higher readings.
Blood pressure measured in a supine position may be 5-10 mmHg higher than in a sitting position and is more predictive of cardiovascular risk.
2. Measurement interval: It is recommended to wait at least 1 minute between measurements, and take 2-3 consecutive measurements, averaging the results to avoid data drift due to short intervals.
II. Equipment Selection and Calibration
1. Arm vs. Wrist Blood Pressure Monitors: Arm blood pressure monitors (upper arm type) are closer to true blood pressure, especially suitable for hypertensive patients; wrist blood pressure monitors may produce errors due to variations in blood vessel conditions.
2. Cuff Size: The cuff width for adults should be 40% of the upper arm circumference, and the length should cover 80% of the upper arm. Improper size will lead to measurement deviations.
3. Regular Calibration: Electronic blood pressure monitors require regular maintenance to prevent cuff aging or tubing wear from affecting accuracy.
III. Environment and Personal State
1. Environmental Factors:
The ideal room temperature is 20-25℃; cold environments can cause vasoconstriction and increase blood pressure.
Avoid noisy environments or direct drafts to prevent interference with measurements.
2. Personal State:
Before measurement, sit quietly for 5-10 minutes, and avoid exercise, smoking, drinking caffeinated beverages, or measuring within 1 hour after a meal.
Emotional stress (such as "white-coat hypertension") can cause a temporary increase in blood pressure; it is recommended to remain relaxed during home monitoring.
IV. Time and Recording Standards
1. Fixed Time Measurement: It is recommended to measure once in the morning after urination and before breakfast, and once before going to bed at night, to reflect the true blood pressure level.
2. Recording Data: Note the measurement time and condition, and provide this information to the doctor during consultations. Avoid adjusting medication based on a single measurement result.
